Chemical additive for hydraulic cement mixes

ABSTRACT

A hydraulic cement mix comprising a hydraulic cement, aggregate in an amount of up to 80% by weight based upon the total weight of said cement mix, sufficient water to effect hydraulic setting of the cement, and an air-entraining additive consisting essentially of a coconut fatty acid diethanolamine produced by reacting alkyl ester of coconut acid with diethanolamine, a capramide diethanolamide and ricinoleic acid, said additive being in an effective amount whereby air will be entrained in said mix in an amount of 3% to 9% by volume of said mix.

BACKGROUND ART

This invention pertains to concrete and cement additive compositions,known as air-entraining admixtures, for incorporation in hydrauliccement mixes, such as portland cement concretes and mortars, but notlimited thereto, for the purpose of increasing the durability in thehardened state of such mixes, to freeze-thaw cycles under conditions ofwater saturation. The increased durability of the cementitious mix undersuch conditions is the result of the development in the plastic portlandcement mix of a system of air bubbles that will remain in the mix afterhardening and meet the specifications of resistance to freezing andthawing stipulated in ASTM designation C-260. This requires that the airvoid system be a specified amount as volume percent of the hardenedcementitious mass, and that it have bubbles within a specified range ofsizes and spacing parameters as designated by ASTM specification C-457.It is well known in the art that in order to meet these requirements, itis necessary to use surface active agents or surfactants to obtain thedesired amount of air entrainment.

There are a number of chemical agents to achieve the specified airentrainment system. Generally, these are organic chemicals which arebroadly classified as soaps and detergents. One of the best knowchemical agents of this type is known in the art as Vinsol resin, whichis a wood resin salt and is the standard against which otherair-entraining agents are tested under ASTM specification No. C-233.Vinsol resin is normally employed as an aqueous alkaline solution thatis added to a plastic, cementitious mix, either alone or in combinationwith other chemical admixtures. In the latter case, the Vinsol resinsolution is added separately because of its chemical incompatibilitywith many other admixtures, due to the fact that the pH and the presenceof calcium and various other ions renders insoluble thealkali-neutralized acids comprising Vinsol resin.

It is also known in the prior art to use a variety of surfactants, bothanionic and nonionic, in the broad class of detergents to obtain adesirable degree of air entrainment in cement, mortar and concrete.Often these are used in various combinations. Some of these surfactantsare sulfated ester ammonium salts of higher primary alcohols (oradditional products with ethylene oxide) alkylbenzenesulfonic acidsalts, salts of petroleum acids, fatty acids and proteinaceoussubstances, and organic salts of sulfonated hydrocarbons.

For example, U.S. Pat. No. 4,249,948 disclosed the use of an alphaolefin sulfonate with a water reducing agent wherein the former acts asan air-entraining agent in a hydraulic cement composition. U.S. Pat. No.4,046,582 disclosed the use of a higher secondary alcohol oxyalkylenesulfate as an air-entraining agent, PCT International Application No. WO85/01,500 (U.S. patent application Ser. No. 537,185; filed 9-29-83)discloses the use of a multicomponent air-entraining additive forhydraulic cement mixes which comprises a three-component mixture of analkylarylsulfonic acid salt, an alkanolamine salt of a fatty acid suchas tall oil, and a nonionic component selected from polyethylene glycolderivatives and diethanolamine adducts of cocamide derived from coconutoil.

However, these air-entraining additives are not entirely satisfactorywith respect to the stability of the air bubbles in concrete, theability to perform in the presence of fly ash in the mix, the effect onimproving the workability of the concrete, the need to use higherdosages of admixtures known in the art, or tendencies to either lose airor to uncontrollably increase air content, as mixing time is extended.Loss of workability is measured by the slump cone in accordance with theAmerican Society for Testing and Materials (ASTM) designation C-143. Thebiggest disadvantage is the reduction in compressive strengths by asmuch as 5% strength loss per 1% increase of entrained air. This loss isdue, in part, to an irregular bubble sizing and the coalescence ofbubbles in the mix causing larger voids, thus reducing the compressivestrengths.

In portland cement concrete, sands vary in fineness from 2.2 to 3.5fineness modulus, which is an empirical figure to determine coarsenessof sand. The higher the fineness modulus (FM), the coarser the sand. Itis well known that as the sand varies, plus or minus, from 2.7, itbecomes increasingly difficult to entrain air in the portland cementconcrete. When sands arrive at the range of an FM of 3.3, large doses ofair entrainment additive are necessary to control the air.

Thus, there exists the continuing need to discover new and improvedair-entraining agents, especially ones that will overcome the problemsdescribed above.

SUMMARY OF THE INVENTION

The present invention is a chemical additive for combining intohydraulic cement mixes, such as portland cement concrete, mortar andgrout, including portland cement mixes which contain various amounts offly ash or slag, for the purpose of entraining air therein, and theresulting improved mixes for incorporating an additive composition.

For purposes of this invention the term "hydraulic cement" refers to allcementitious compositions based primarily on silicates capable of beingset and hardened by the action of water, such as portland cements,sulfate-resisting cement, blast furnace cements and pozzolanic cements,including cement mixes where a portion of the portland cement has beenreplaced by fly ash or slag. The term "portland cement" refers to allcementitious composition which have a high content of tricalciumsilicate, conforming with the specifications set forth in ASTMdesignation No. C-150, and the portland blended cements such as thosedescribed in ASTM designation No. C-595.

Broadly, the invention comprises a portland cement mix including fly ashand/or slag cement, aggregate, sufficient water to effect hydraulicsetting of the cement, and an air-entraining additive consistingessentially of an ester-derived coconut acid diethanolamide, also knownas cocoamide diethanolamine, or cocamide DEA, as more fully describedhereinafter. The cocamide DEA can be added in any convenient form,although it is most convenient to add it as an aqueous solution.

The dosage used should be an amount which is effective in entraining thedesired amount of air, usually measured as a volume percentage of thehydraulic cement mix. As is known in the art, the amount of airentrained desired and intended to be is usually in the range of 3% to 9%air, by volume. This amount of air is achieved by a dosage ofester-derived cocamide DEA of between about 0.001% and 0.01% by weightbased upon the weight of the cement.

The unexpected and nonobvious result obtained by employing ester-derivedcocamide DEA by itself in a cementitious system undergoing extendedmixing is to yield with a favorable dosage response an excellent airvoid system stable in the plastic cementitious system and having adesirable improved size distribution in the cementitious system afterhardening, while yielding increased compressive strengths over referencemixes.

It is therefore the object of this invention to provide improvedair-entrained portland cement mixes, including concrete, mortar, groutand dry mixes, which include an additive composition that willadvantageously entrain an air void system having desired characteristicswhen said additive is employed over a relatively wide dosage range, orhave a superior dosage response relative to functionally similaradditives known in the art.

It is another object of this invention to provide improved strengthresults which include an additive composition that will entrain an airvoid system and increase compressive strengths over known air-entrainingagents.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The term "cocamide DEA" is a name the Cosmetic Toiletry, and FragranceAssociation, or CTFA, has applied to a wide variety of coconutacid-based compositions comprising diethanolamine adducts of cocamide.Although they are all called cocamide DEA, they are produced by avariety of reactions. In one type of reaction, a 1:1 molar ratioreaction is produced between diethanolamine and either a coconut acid,also known as coconut fatty acid; an alkyl ester, usually methyl ester,of a coconut acid; or a coconut acid-based triglyceride, such as coconutoil. In another type of reaction, a 2:1 molar ratio is employed in theso-called Kritchevsky process, which is described in U.S. Pat. No.2,094,609 to W. Kritchevsky.

The present invention has resulted from the unexpected discovery thatcocamide DEA, produced by the methyl ester process, although otheresters could be used, will, when employed by itself in effective amountsin hydraulic cement mixes, produce stable volumes of air havingdesirable size and distribution, such as are employed to increase thefreeze-thaw durability of hydraulic cement mixes or to produceair-entrained hydraulic cement mixes for other reasons. Additionally, itwas discovered that higher compressive strengths were beneficiallyachieved using the additive of the invention. For convenience, cocamideDEA derived by the ester process will be described as ester-derivedcocamide DEA.

Ester-derived cocamide DEA is commercially available under thetrademarks Comperlan KD and Standamid KD from Henkel International GmbH,Dusseldorf, West Germany, and Ninol 49CE from Stepan Company,Northfield, Ill.

The term "coconut acid" usually means a mixture of fatty acids derivedfrom the hydrolysis of coconut oil, and having acid chain lengthsvarying from 6 to 18 carbons, but mostly 10, 12, and 14 carbons. Apreferred coconut acid is one consisting approximately of the followingrange of fatty acids:

    ______________________________________                                        Lauric Acid            46-58%                                                 Myristic Acid          15-23%                                                 Palmitic Acid           8-14%                                                 Stearic and Oleic Acid  7-24%                                                 ______________________________________                                    

Further, the coconut acid preferably should have an acid value ofbetween about 246 and 260, a saponification value of between about 247and 262, and an iodine value of between about 10 and 20.

The resulting cocamide DEA reaction product from the reaction of thecoconut ester and diethanolamine will preferably comprise approximatelythe following composition and have a pH value (of a 1% solution) in therange of 8-10 and a density in the range of 8.3 to 8.5 pounds pergallon, preferably about 8.43 pounds per gallon:

    ______________________________________                                        Coconut Amide          85-90%                                                 Coconut Ester           0-10%                                                 Free Coconut Acid       0-0.5%                                                Free Diethanolamine     0-5%                                                  Water                  0.0.5%                                                 ______________________________________                                    

In the practice of the present invention the additive is incorporatedinto hydraulic cement mixes such as portland cement concretes andmortars in amounts sufficient to yield an entrained air void system ofthe proper amount and quality. As a practical matter the additive isincorporated into the mix as an aqueous solution, which may be of anyconvenient concentration.

The additive may be incorporated into the mix as a portion of the mixwater but it may also be incorporated in any other convenient manner,including adding it to the dry mix or aggregate before the water isincorporated therein.

The term "entrained air" is intended to have the meaning found in theart, namely that by using an agent for that purpose, an intended anddesirable amount of air, i.e, 3% to 9%, by volume, based upon the totalvolume of the hydraulic cement mix, will be incorporated into theplastic hydraulic cement mix and ultimately in the hardened concrete. Bythis means, the durability or workability of a plain or nonair-entrained concrete or mortar can be improved. Further, the materialswhich comprises a concrete mix, and the mixing itself, can introducesome air into the mix, and often, such is referred to as entrapped air.The additive of the present invention is beneficial in that itunexpectedly produced an intended and desirable amount of airentrainment which further proved to be stable during extended mixing andto be beneficial to the hardened concrete because it resulted inincreased compressive strengths.

The term "aggregate" is intended to include both coarse aggregate, suchas crushed stone or gravel, and fine aggregate, such as sand, as iscommon in the art. In general, the aggregate in mortars may be sand orother fine aggregate meeting the requirements of ASTM designation No.C-33. The proportions of coarse aggregate and fine aggregate will varydepending upon the properties and use of the concrete or mortar. In mostcases, although not limited thereto, the coarse aggregate will be withinthe broad range of 2 inches (7.6 cm) to 4 mesh, while the size of thefine aggregate will be within the broad range of about +4 mesh to -200mesh U.S. Standard Sieve (ASTM C-11). The coarse aggregate will usuallybe of mineral origin, such as gravel or crushed limestone, but it may bea manufactured aggregate, such as a slag. The amount of aggregate can beup to 80% by weight, based upon the total weight of the hydraulic cementmix, with the range of 20% to 80% by weight being preferred.

For both mortars and concretes, the amount of water employed generallywould be enough to effect hydraulic setting of cementitious material inthe mix and to provide suitable workability in the plastic state. Thiswould broadly range from about 15% to 30% by weight of the cementitiousmaterials in mortars and about 50% to 85% by weight of the cementitiousmaterial in concrete mixes. The precise proportion of water will dependon the end use of the cementitious mix as well as on its composition.

In order to illustrate the effectiveness of ester-derived cocamide DEAin generating air bubbles, as compared to other known and potentialair-entraining agents, selected agents were tested in a modified HenkelFoam Test. The following is the "Foam Test Methodology" stated in aHenkel International GmbH technical bulletin for Standamid brandalkanolamides:

"Foam Test Methodology"

"The following test procedure, developed by Henkel, is a simple way tomake accurate determination of foam volume and foam drainage:

"Prepare a 10% aqueous solution of product being evaluated. Add six (6)grams of this solution to 144 grams of water, hardness 50 ppm, heated to29° C.±1° C. Agitate for ten (10) seconds in an osterizer-type blender.Stir/medium speed agitation. Measure the initial foam volume to thenearest 5 ml, ad then record the position of the foam/water interfaceafter 3.5 minutes. This later reading represents the foam drainage."

The test was modified by using 5% by weight aqueous solutions andplacing 300 cc of each solution in a measuring container, graduated inmillimeters, for use with the osterizer-type blender. As per the Henkeltest, the solution is agitated for ten (10) seconds at medium speed. Themixing generates a certain amount of foam which floats above a liquidinterface and which is measured as the initial interface. The containeris then allowed to sit undisturbed for one (1) hour. When this is done,some or all of the foam returns to liquid. This liquid return is called"foam drainage," and a new liquid-foam interface, or final interface, isestablished somewhere between the initial interface and the 300 cc levelat which the liquid started. The amount of the final liquid-foaminterface is then measured. The percent of foam drainage is calculatedby dividing the difference between the 300 cc level of each solution andthe initial interface and multiplying by 100. The results for eachtested agent are reported in Table I. The amount of foam drainage isconsidered to be a reflection on the stability of the bubbles generated.

Also reported in Table I is the unit weight of the bubbles generated,called bubble density. To obtain the unit weight, a further test wasdone using the same modified Henkel foam test methodology. Three hundred(300) cc of each solution were placed in the osterizer-type blender,agitated for ten (10) seconds at medium speed, and then allowed to situndisturbed for one (1) hour. The bubbles or foam remaining were thenremoved from the mixer, placed in a volumetric measuring unit andweighed. The values were then converted to weight per one cubic foot.

                  TABLE I                                                         ______________________________________                                                         Foam       Bubble Density                                    Agent Tested     Drainage (%)                                                                             Pounds/Foot                                       ______________________________________                                        Cocamide DEA     16.7       22.9                                              (Ester-Derived)*                                                              Cocoamide DEA    96.6       10.4                                              (Kritchevsky Process Derived)                                                 Cocoamido Proply Betaine                                                                       99.4       1.4                                               Cocoamide DEA    86.0       12.6                                              (Ester-Derived)**                                                             Cocoamide DEA    97.3       4.8                                               (Oil Derived)                                                                 Sodium Lauryl Sulfate                                                                          99.3       1.5                                               Ammonium Lauryl Sulfate                                                                        98.0       1.7                                               Lauryl Sulfate Triethanolamine                                                                 99.8       1.3                                               Sodium Octyl Sulfate                                                                           99.2       0.9                                               Disodium Mono-Oleamide/                                                                        98.3       1.7                                               Diglycol Sulfosuccinate                                                       Wood Resin Salts 98.1       1.8                                               Alkyl Phenoxy Polyethoxy                                                                       98.0       1.9                                               Ethanol                                                                       ______________________________________                                         *Supplied by Source I (Henkel)                                                **Supplied by Source II (Stepan)                                         

These results demonstrate that ester-derived cocamide DEA has a superiorcombination of bubble volume retention as measured by the low foamdrainage and greater unit weight. Of particular interest is theperformance against wood resin salts, such as are used in Vinsol resinair-entraining admixtures, as compared to ester-derived cocamide DEA.The ester-derived cocamide DEA from Source I performed the best andresulted in only 16.7% foam drainage versus 98.1% for the wood resinsalts. Also, the ester-derived cocamide DEA (Source I) tested at a 22.9lb./cu. ft. unit weight versus 1.8 lb./cu. ft. for the wood resin salts.The cocamide DEA from Source II was not as good a performer as that fromSource I, but still had an acceptable combination of foam drainage(86.0%) and bubble density (12.6 lb./cu. ft.), especially compared,e.g., to the Kritchevsky process-derived cocamide DEA, which had arelatively high bubble density of 10.4 lb./cu. ft., but a very high foamdrainage of 96.6%. Thus, an ester-derived cocamide DEA having a foamdrainage of at most about 86% or less and a bubble density of 12lbs./cu. ft. or more is preferred.

The reason for the greater unit weight for ester-derived cocamide DEA isspeculated to be due to greater thickness of the bubble walls. When aportion of the bubbles produced in the modified Henkel foam test isplaced on a spherical depression slide and examined using a standardlaboratory microscope, the cocamide DEA bubbles from Source I are seenas spherical bubbles having thicker walls, while the wood resin bubblesare relatively thin-walled and tend to be less than spherical with someshapes being oblong. This sort of differences should produce a morestable air and uniform bubble structure in a hydraulic cement mixenvironment.

For the purpose of illustrating the advantageous results obtainable bythe practice of the present invention in hydraulic cement mixes,concrete mixes were prepared according to ASTM designation Nos. C-494and C-233. Mixes containing the additives of the present invention andVinsol resin additives were made. The sequence of operations in thisprocedure were: preparation of concrete mixes with a nominal slump of 2inches±1/2 inch and a dosage of air-entraining admixture per 100 poundsof cement such as would produce an air content of 5.5%±0.5% by volume ofthe concrete. Each mix was designed for a total of 517 lbs./yd.³portland cement, a sand-aggregate ratio of 0.89, and the samewater-to-cement ratio (0.31). The concrete, with an appropriate amountof water to attain the specified slump value was then mixed in aconcrete mixer of 6 cubic feet capacity. Next, 6"×12" cylinder specimenswere taken for subsequent determinations of compressive strengths andthe parameters of the air void system after hardening. The initial aircontent of a sample of the plastic concrete was determined by thepressure-meter method as described in ASTM standard test method NO.C-231 and the slump value, which is an index of workability, wasdetermined in accordance with ASTM standard method No. C-143.

The results of the tests are shown in Table II and a comparison is madebetween an ester-derived cocamide DEA (from Source I) and Vinsol resinair-entraining agent. In each case the rate of hardening was within theASTM No. C-233 specification. It can be seen from Table II that theester-derived cocamide DEA produced the intended and desirable amount ofair as well as favorable air retention and further achieved significantcompressive strength gains in comparison to the concrete containingVinsol resin.

                  TABLE II                                                        ______________________________________                                        TEST RESULTS                                                                             Vinsol             Difference                                                 Resin  Ester-Derived                                                                             As Percent                                                 (Control)                                                                            Cocamide DEA                                                                              Of Control                                      ______________________________________                                        Entrained Air (%)                                                                          6.0      5.7                                                     Compressive Strength                                                          (PSI)                                                                         1 Day        1950     2360        121%                                        3 Days       3410     3950        116%                                        7 Days       4140     4530        109%                                        28 Days      5235     5640        108%                                        ______________________________________                                    

In order to evaluate the entrained air in the hardened concrete, one ofthe specimens from the concrete made using ester-derived cocamide DEAand produced in the tests discussed above was examined microscopicallyin accordance with ASTM standard method No. C-457, with the resultsbeing reported in Table III.

                  TABLE III                                                       ______________________________________                                        AIR VOID ANALYSIS                                                             Air Content  Paste#      Specific Spacing                                     % by Volume  Content     Surface  Factor                                      (Plastic)                                                                            (Hardened)                                                                              % by Volume Inches .sup.-1                                                                       L, Inch                                   ______________________________________                                        5.7    6.7       23.83       500    0.007                                     ______________________________________                                         #Sum of the volumes of portland cement and mixing water                  

As can be seen, the spacing factor L is 0.007 inch, which is less thanthe 0.008 inch factor and more than 0.004, which is the usualrecommended limits on the spacing factor for durable, i.e., resistant tofreezing and thawing, concrete.

In another test, a comparison was made between plain concrete, which wasthe control and contained no air-entraining agent, a Vinsol resin mixand a mix containing an ester-derived cocamide DEA (Source I). The mixdesigns were similar to those in Table II except that the slumps were 4inches±1/2 inch. As can be seen in Table IV, the ester-derived cocoamideDEA achieved significantly higher compressive strengths than the Vinsolresin and the plain control mix, and produced desirable air entrainment.

                  TABLE IV                                                        ______________________________________                                                             Vinsol   Ester                                                         Control                                                                              Resin    Derived                                                       Mix    Mix      DEA Mix                                         ______________________________________                                        Dosage (% by Weight)                                                                          --       0.0087   0.0039                                      of Cement                                                                     Air Content (% by Volume)                                                                     --       5.1%     5.8%                                        at 10 Minutes                                                                 7 Day Avg. PSI  3497     3520     3820                                        (% Compared to Plain)    (100.7)  (109.2)                                     28 Day Avg. PSI 4400     4316     4733                                        (% Compared to Plain)     (98.1)  (107.6)                                     ______________________________________                                    

In yet another test, extended mixing time was done with a series ofconcrete mixes containing an ester-derived cocamide DEA from Source I(Mix A), ester-derived cocamide DEA from Source II (Mix B), and aKritchevsky process-derived cocamide DEA (Mix C), such as used in thetests reported in Table I. This test was done to establish theperformance of stability of the air bubbles over a period of mixing timesuch as would be comparable to concrete mixed in the field. The mixdesign is shown in Table V. The mixing was done continuously for 50mixtures, except when samples were taken to measure the air content. Atthat time additional water was added to restore the slump, as close aspossible to its original value.

                  TABLE V                                                         ______________________________________                                        Concrete Mix Design                                                           ______________________________________                                        Cement          564 lbs. Medusa Type 1                                        Stone (2% H.sub.2 O)                                                                          1834 lbs. Sandusky Limestone                                  Sand (6% H.sub.2 O)                                                                           1377 lbs. Twin Lakes                                          Water           202 lbs.                                                      Additive        .0039% per weight of cement                                   Mixing  Mix A      Mix B        Mix C                                          Time   Slump   Air    Slump  Air   Slump Air                                 ______________________________________                                         4 min. 41/2"   4.5%   4"     6.5%  41/2% 3.5%                                15 min. 4"      6.5%   4"     7.0%  3"    3.0%                                30 min. 3"      6.5%   3"     5.5"  1"    2.5"                                45 min. 21/2"   6.5%   11/2"  4.0%  --    --                                  50 min. 33/4"   6.6%   43/4"  4.5%  --    --                                  (remix).sup.1                                                                 ______________________________________                                         .sup.1 Water was added to bring slump back to approximate original slump.

As can be seen in Table V, the additive of the invention, namely anester-derived cocamide DEA, achieved a desirable amount of airentrainment, which proved to be relatively stable with extending mixing.This can be contrasted with Mix C which contained a Kritchevskyprocess-derived cocamide DEA and which produced only minimal airentrainment and which showed poor air retention. In fact, the test wasstopped after 30 minutes because air dropped below the desirable minimumof 3% air entrainment. The air content and retention values certainlyseem to correlate with the foam drainage and bubble density data shownin Table I and demonstrate that ester-derived cocamide DEA is a superiorair-entraining agent.

Further testing was conducted to confront the problem of holding aircontents stable in varying FMs on fine aggregate used in concrete. Itwas noted that with the straight, ester-derived cocamide DEA and sandswith FMs in the 3.2 to 3.5 range, larger than normal doses were neededto achieve satisfactory air entrainment. Unexpected results wereachieved when varying percentages of capramide DEA were added to theester-derived cocamide DEA. Depending upon the percentage of capramidein relation to the ester-derived cocamide DEA, air contents continued torise in coarse sands with the increased dosage of capramide DEA.Following tests were run on sands with an FM of 3.3, and the resultswere as follows:

                  TABLE VI                                                        ______________________________________                                        Mixing  6% Ester  51/2% Ester/                                                                             5% Ester/                                                                             4% Ester/                                Time    0% Capric 1/2% Capric                                                                              1% Capric                                                                             2% Capric                                ______________________________________                                         8 minutes                                                                            3.5       4.2        4.6     5.1                                      18 minutes                                                                            3.5       4.5        5.1     5.6                                      28 minutes                                                                            3.75      4.5        5.2     6.2                                      38 minutes                                                                            3.7       4.2        5.3     6.4                                      ______________________________________                                         Note: Initial slump: 21/2"-3".                                                Note: Water added at 28 minutes to renew initial slump.                  

The unobvious results obtained by the blending of the capramide DEA andester-derived cocamide DEA show an increased and stable air entrainmentfor problem sands in the concrete industry. The capramide DEA ismanufactured from predominantly capric fatty acids (C-10). It isbasically a foam booster with much less viscosity-building effects thanhigher alkanolamines. This facilitates enhancement of foam volume,density, lubrication and stability. Depending upon the variabilities insand, the blending of coconut acid diethanolamine (produced by reactingan alkyl ester and a coconut acid with a diethanolamine) and a capramidediethanolamine, assist in the production of stable volumes of air.

The foregoing addition of capramide DEA solved the problem of achievingsatisfactory air entrainment when the sands utilized had a finenessmodulus in the range of 2.4 to 3.0, however, air entrainment decreasedwhen fly ash or a sand having a significantly lower fineness modulus wasintroduced into the mix. The foregoing problem was solved by addingricinoleic acid to the capramide DEA and the ester-derived cocamide DEA.Tests were conducted on mixes using 14% type "F" fly ash with theforegoing additive, and the results were as follows:

                  TABLE VII                                                       ______________________________________                                                  4.0% Ester   Vinsol                                                           2.5% Capric  Resin                                                            1.0% Ricinoleic Acid                                                                       Mix                                                    Mixing Time Slump    Air       Slump  Air                                     ______________________________________                                        18 minutes  6"       8.5%      63/8"  7.5%                                    36 minutes  41/4"    7.75%     41/2"  6.5%                                    54 minutes  23/4"    6.25%     3"     5.25%                                   72 minutes  2"       5.5%      11/4"  4.75%                                   83 minutes  43/4"    6.0%      3"     5.25%                                   (remix).sup.1                                                                 ______________________________________                                         .sup.1 12 oz. of water was added to increase slump                       

The data in the above table indicates that the blending of ricinoleicacid, capramide DEA and ester-derived cocamide DEA resulted in increasedair entrainment in mixes containing fly ash. Not only did airentrainment increase with the addition of ricinoleic acid, such anaddition did not adversely affect compressive strengths, but ratherincreased same as shown by the following table:

                  TABLE VIII                                                      ______________________________________                                        COMPRESSIVE STRENGTHS (PSI)                                                               4.0% Ester     Vinsol                                                         2.5% Capric    Resin                                              Drying Time 1.0% Ricinoleic Acid                                                                         Mix                                                ______________________________________                                        1 Day       1256           1094                                               3 Days      2484 At        2158 At                                            7 Days      2740 8.5% Air  2536 7.5% Air                                      28 Days     4628 6" Slump  4518 63/8" Slump                                   ______________________________________                                    

The foregoing increase in compressive strength with an increase in airentrainment was not expected since typically an increase in airentrainment results in a decrease in compressive strength. Thus, theblending of ricinoleic acid, capramide DEA and ester-derived cocamideDEA provide two significant benefits, i.e., increased air entrainmentand compressive strength.

Similar results were achieved using a blend of ricinoleic acid,capramide DEA and ester-derived cocamide DEA with a sand having afineness modulus of 2.26. Typically, when sand has such a low finenessmodulus, it is difficult to achieve air entrainment of 4.0% or greaterwith standard dosages. It should be noted that if air entrainment dropsto 3.0% or less, it is assumed that the cement does not include anyentrained air. Tests were conducted on mixes utilizing sands having afineness modulus of 2.26 with a blend of ricinoleic acid, capramide DEAand ester-derived cocamide DEA, and the results were as follows:

                  TABLE IX                                                        ______________________________________                                                  4.0% Ester   Vinsol                                                           2.5% Capric  Resin                                                            1.0% Ricinoleic Acid                                                                       Mix                                                    Mixing Time Slump    Air       Slump  Air                                     ______________________________________                                        18 minutes  5"       5.0%      4"     4.75%                                   36 minutes  23/4"    4.5%      21/2"  4.0%                                    54 minutes  21/4"    4.0%      11/4"  3.5%                                    72 minutes  11/2"    3.75%     3/4"   3.0%                                    83 minutes  41/2"    4.50%     31/4"  3.75%                                   (remix).sup.1                                                                 ______________________________________                                         .sup.1 13 oz. of water was added to increase slump                       

Thus, the blending of ricinoleic acid with capramide DEA andester-derived cocamide DEA increased the percentage of air entrainmentto acceptable levels in mixes using sands having an extremely lowfineness modulus. Furthermore, as in the previous case of fly ash, theblending of ricinoleic acid with capramide DEA and ester-derivedcocamide DEA also significantly increased the compressive strength ofthe resulting mix as shown in the following table:

                  TABLE X                                                         ______________________________________                                        COMPRESSIVE STRENGTHS (PSI)                                                               4.0% Ester     Vinsol                                                         2.5% Capric    Resin                                              Drying Time 1.0% Ricinoleic Acid                                                                         Mix                                                ______________________________________                                        1 Day       1463           1252                                               3 Days      2318 At        2130 At                                            7 Days      3628 5.0% Air  3439 4.75% Air                                     28 Days     4886 5" Slump  4492 4" Slump                                      ______________________________________                                    

The foregoing results as to compressive strength provide a furtherunexpected result, viz., an increase in compressive strength with anincrease in slump. Thus, in this case, the blending of ricinoleic acidwith capramide DEA and ester-derived cocamide DEA increased airentrainment, compressive strength and slump.

To further determine the effects of blending ricinoleic acid withcapramide DEA and ester-derived cocamide DEA, tests were conducted usingsuch an additive with sand having a fineness modulus of 3.0. The resultsof these tests, which were conducted at 134° F., are shown in thefollowing table:

                  TABLE XI                                                        ______________________________________                                                  4.0% Ester   Vinsol                                                           2.5% Capric  Resin                                                            1.0% Ricinoleic Acid                                                                       Mix                                                    Mixing Time Slump    Air       Slump  Air                                     ______________________________________                                        18 minutes  7"       7.2%      71/4"  6.8%                                    36 minutes  51/2"    7.3%      41/4"  6.5%                                    54 minutes  3"       6.5%      2"     5.25%                                   72 minutes  21/4"    5.6%      13/8"  4.5%                                    83 minutes  6"       6.75%     6"     5.0%                                    (remix).sup.1                                                                 ______________________________________                                         .sup.1 13 oz. of water was added to the 4.0% Ester, 2.5% Capric and 1.0%      Ricinoleic Acid mix to increase slump, and 1 lb. 8 oz. of water was added     to Vinsol Resin Mix to increase slump.                                   

Here again, the addition of ricinoleic acid to capramide DEA andester-derived cocamide DEA significantly increased air entrainment evenwith sands having an average fineness modulus, i.e., 3.0. As in theprevious examples, the blending of ricinoleic acid with capramide DEAand ester-derived cocamide DEA also caused a significant increase incompressive strength of the resulting mix, as shown by the followingtable:

                  TABLE XII                                                       ______________________________________                                        COMPRESSIVE STRENGTHS (PSI)                                                               4.0% Ester     Vinsol                                                         2.5% Capric    Resin                                              Drying Time 1.0% Ricinoleic Acid                                                                         Mix                                                ______________________________________                                        1 Day       1556           1314                                               3 Days      3034 At        2632 At                                            7 Days      4248 7.2% Air  3688 6.8% Air                                      28 Days     5434 7" Slump  4806 71/4" Slump                                   ______________________________________                                    

In this case the blending of ricinoleic acid with capramide DEA andester-derived cocamide DEA provided a very significant increase incompressive strength, approximately 15%.

From the foregoing, it is obvious that the blending of ricinoleic acidwith capramide DEA and ester-derived cocamide DEA provided a number ofdesirable results. For example, the use of ricinoleic acid as part ofthe additive increased air entrainment regardless of the finenessmodulus of the sand utilized or whether fly ash was introduced into themix. Even with extended mixing times, the percentage of air entrainmentremained above acceptable limits. Thus, mixes containing ricinoleic acidand capramide DEA and ester-derived cocamide DEA can tolerate longertravel and mix time to the ultimate use site. At the use site, the userwould typically add water to increase the slump which may increase airentrainment, however, it has been found that such an increase isgenerally insignificant. With the addition of ricinoleic acid tocapramide DEA and ester-derived cocamide DEA, air entrainment willremain at acceptable levels even with extended mixing times and theaddition of water does not have to be depended upon to slightly increaseair entrainment. It has been further found that mixes containingricinoleic acid, capramide DEA and ester-derived cocamide DEA cantolerate relatively high temperatures for extended period of times. Forexample, the temperature utilized for the test in Tables XI and XII was134 degrees F. Thus, high temperatures do not have an adverse affect onmixes utilizing ricinoleic acid in combination with capramide DEA andester-derived cocamide DEA. This is not the case with mixes utilizingother types of additives. In summary, the blending of ricinoleic acidwith capramide DEA and ester-derived cocamide DEA produced verydesirable and beneficial results.

While the invention has been described with reference to certainpreferred embodiments thereof, those skilled in the art will appreciatethat various modifications and substitutions can be made withoutdeparting from the spirit of the invention. In particular in the contextof this invention, aqueous solutions of the components described mayhave added thereto small amounts of compatible chelating agents foralkaline earth cations such as magnesium or calcium which normally occurin ordinary water but which also tend to precipitate surface activeagents. Also, small amounts of compatible cosmetic coloring agents orbiocides or the like may be added. Further, the admixture of the presentinvention could be used with other admixtures added for their intendedpurposes, e.g., the use of water-reducing admixtures to increasecompressive strength or accelerating or retarding admixtures to changethe rate of set of the hydraulic cement mixes. Thus, it is intended thatthe invention will be limited only by the scope of the claims whichfollow.

We claim:
 1. A hydraulic cement mix comprising a hydraulic cement,aggregate, sufficient water to effect hydraulic setting of the cement,and an air-entraining additive consisting essentially of a coconut aciddiethanolamide produced by reacting alkyl ester of coconut acid withdiethanolamine, said additive being in an effective amount of between0.0013% and 0.004%, a capramide diethanolamine in an effective amount ofbetween 0.008% and 0.0024%, and ricinoleic acid in an effective amountof between 0.0003% and 0.001% by weight based upon the weight of thecement, whereby air will be entrained in said mix in an amount of 3% to9% by volume of said mix.
 2. A hydraulic cement mix in accordance withclaim 1, wherein said hydraulic cement comprises portland cement.
 3. Ahydraulic cement mix in accordance with claim 1, wherein said aggregateis present in an amount of up to 80% by weight, based upon the totalweight of the hydraulic cement mix.
 4. A hydraulic cement mix inaccordance with claim 1, wherein said aggregate is present in an amountof from 20% to 80% by weight.
 5. A hydraulic cement mix in accordancewith claim 1, wherein said coconut acid is comprised as follows:

    ______________________________________                                        Lauric Acid            46-58%                                                 Myristic Acid          15-23%                                                 Palmitic Acid           8-14%                                                 Stearic and Oleic Acid  7-24%                                                 ______________________________________                                    


6. A hydraulic cement mix in accordance with claim 1, wherein saidcoconut acid diethanolamide reaction product comprises:

    ______________________________________                                        Coconut Acid Diethanolamide                                                                           85-90%                                                Coconut Acid Alkyl       0-10%                                                Coconut Acid             0-0.5%                                               Diethanol Amine          0-5%                                                 ______________________________________                                    


7. A hydraulic cement mix in accordance with claim 1, wherein saidreaction is conducted with equal moles of coconut alkyl ester anddiethanolamine.
 8. A hydraulic cement mix in accordance with claim 1,wherein said capramide diethanolamine comprises:

    ______________________________________                                        Octanoic Acid C.sub.8                                                                         0.5-1.5%                                                      Capric Acid C.sub.10                                                                          94-98%                                                        Lauric Acid C.sub.12                                                                          1.5-2.5%                                                      ______________________________________                                    


9. A hydraulic cement mix in accordance with claim 1, wherein saidricinoleic acid comprises:12-Hydroxy-9-Octadecenoic Acid.
 10. A processfor entraining air in a hydraulic cement mix, which includes hydrauliccement, aggregate, and sufficient water to effect hydraulic setting ofthe cement, comprising the addition of an additive consistingessentially of coconut acid diethanolamide, produced by reacting alkylester of coconut acid with diethanolamine, said additive being in aneffective amount of between 0.0013% and 0.004%, a capramidediethanolamine in an effective amount of between 0.008% and 0.0024%, andricinoleic acid in an effective amount of between 0.0003% and 0.001% byweight based upon the weight of the cement, whereby air will beentrained in said mix in an amount of 3% to 9% by volume of said mix.11. A process for entraining air in a hydraulic cement mix in accordancewith claim 10, wherein said hydraulic cement comprises portland cement.12. A process for entraining air in a hydraulic cement mix in accordancewith claim 10, wherein said aggregate is present in an amount of up to80% by weight, based upon the total weight of the hydraulic cement mix.13. A process for entraining air in a hydraulic cement mix in accordancewith claim 10, wherein said coconut acid is comprised as follows:

    ______________________________________                                        Lauric Acid            46-58%                                                 Myristic Acid          15-23%                                                 Palmitic Acid           8-14%                                                 Stearic and Oleic Acid  7-24%                                                 ______________________________________                                    


14. A process for entraining air in a hydraulic cement mix in accordancewith claim 10, wherein said coconut acid diethanolamide reaction productcomprises:

    ______________________________________                                        Coconut Acid Diethanolamide                                                                           85-90%                                                Coconut Acid Alkyl       0-10%                                                Coconut Acid             0-0.5%                                               Diethanol Amine          0-5%                                                 ______________________________________                                    


15. A process for entraining air in a hydraulic cement mix in accordancewith claim 10, wherein said reaction is conducted with equal moles ofcoconut alkyl ester and diethanolamine.
 16. A process for entraining airin a hydraulic cement mix in accordance with claim 10, wherein saidcapramide diethanolamine comprises:

    ______________________________________                                        Octanoic Acid C.sub.8                                                                         0.5-1.5%                                                      Capric Acid C.sub.10                                                                          94-98%                                                        Lauric Acid C.sub.12                                                                          1.5-2.5%                                                      ______________________________________                                    


17. A hydraulic cement mix in accordance with claim 10, wherein saidricinoleic acid comprises:12-Hydroxy-9-Octadecenoic Acid.
 18. A productmade in accordance with the process of claim 10.